Data analysis

Data were descriptively summarized using median and interquartile ranges for continuous variables and frequencies and percentages for categorical variables. The overall CAA score for the primary analysis was defined as the mean of the region specific scores. Associations of sex and APOE4 with CAA score were examined using linear regression models with adjustment for age, Braak stage, and Thal amyloid phase. Associations between CAA, sex, and APOE4+ with log-transformed Aβ and apoE levels were examined using multivariate logistic regression. The parameter estimates were exponentiated to obtain estimates of relative levels in one group compared to another. Age, Braak stage and Thal amyloid phase were adjusted for all models. All statistical tests were two-tailed. Analyses were primarily performed using SAS statistical software (SAS Institute Inc, Cary, NC).